subs for Sonus Faber Cremona M floor standing

I am using the JL Audio F110 with what are already essentially "full range" speakers and love it! looking for a second to add to the system, not for overall gain but just smoothing of the room nodes. That being said, I would probably be just as happy with the Velodyne DD10 (or especially, the new DD+ series). Both companies make incredible products that are able to integrate into almost any room and any system. Can't see going wrong with either of these.

JLs not only have beastly build quality, they have a suite of controls and features to blend the sub with your speakers *and* the room--adjustment controls for continuously variable phase control over a wide range, volume, crossover, a polarity switch, and ARO (automatic room optimization) complete with calibrated microphone.

I've heard a pair of Magnepan 20.1's augmented with a pair of Fathom F212's and the integration was completely seamless. Although the JLs are capable of great power and thunder, they are also the best I've heard on seamlessly integrating for a music system and never calling attention to themselves.

I have an audiobuddy who uses the $679 sealed SVS to augment his Magnepan 1.7s and he likes it a lot. The SVS's seem to be a pretty good value. Their 13" driver reminds me of the JL approach, and their $2K 3-port model (using that 13" driver) has four rolloff profiles, depending on how many ports you plug. All 3 ports plugged creates a gentle rolloff that extends usable FR to around 14 Hz. That would be a good config for music. The gentle rolloff also avoids the big port resonance boom, so again, it's better for blending for music than with all ports firing.

I just acquired a REL T5 to mate with my SF GH's. I have a very small room, so a larger sub most likely would quickly overload the room. What size is your room? A JL is probably a good choice for a larger room, not so good for a smaller room.

Daveyf have to disagree.......even a large JL sub can be used in a small room by decreasing the output, yes you could easily get by with a less expensive option but you could decrease the larger subs output to match the room and speakers IMHO.

I disagree with Rauliruegas about how to use the subs. I have found it ALWAYS better to run the speakers full range and only use the subs to augment the very bottom end. True, you don't relieve the amp of some work but on the other hand you are not running the signal through another crossover which will invariably degrade the sound. If you like the sound you now have and just wish to augment the bass I suggest that this is the way to go. If you want to play louder with more boom go the other way.